Various advertisement fixtures, such as advertisement paper, billboards, and luminous advertisement fixtures, have been recently used in advertising products of various companies or various businesses. Such an advertisement fixture uses various kinds of pictures, phrases, photographs, patterns, etc., so as to increase recognition of desired information to be communicated to a purchaser, and particularly, many kinds of advertisement fixtures using a lighting fixture have been developed so as to make it possible to properly communicate desired information to a purchaser at night time or at a place under low illumination.
Generally, such an advertisement fixture using a lighting fixture includes a cover plate having transparent or semitransparent material having light transmission. The cover plate exiting light emitted from an light source, such as a fluorescent lamp or a lighting emitting diode (LED), etc., outward while diffusing the light, and also hides the light source. The cover plate may have a thin film engraved with a picture, a phrase, a pattern, etc. attached to a surface thereof, or may have its own shape of a specific character or a picture, etc.
Also, in addition to an advertisement fixture, a lighting fixture, such as a fluorescent lamp, a stand light, a street light, or a light for an interior design, etc. employs a cover plate.
Most cover plates employed in a typical lighting fixture are generally manufactured by adding polymeric particulates, to which inorganic particles, styrene-based or acryl-based polymeric particles, etc. are partially cross-linked.
However, the conventional cover plate has high specific gravity so that its weight is heavy and much manufacturing cost is required. Also, the conventional cover plate has a superior optical diffusivity, but has a low light transmission, so there is a problem that a luminance-characteristic thereof is generally low.
Particularly, when an advertisement fixture becomes larger, the size of a cover plate employed therein increases and the thickness thereof also increases. However, when the thickness of a cover plate increases as such, the number of corpuscles included therein also increases in proportion to the increases of thickness thereof. Accordingly, light transmission remarkably decreases so that luminance also notably decreases.